Effect of maternal zinc deficiency of food restriction on rat fetal pancreas. 2. Insulin and glucagon.

The influence of a maternal dietary deficiency of zinc, or food restriction on the content and in vitro secretion of pancreatic hormones was measured in rat fetuses on day 19 of gestation. Pregnant Sprague-Dawley rats were fed a zinc-deficient diet (0.4 +/- 0.1 ppm zinc) ad libitum or a zinc-supplemented control diet (100 ppm zinc) either ad libitum or with restricted intake. The insulin content of the fetal pancreas was lower in fetuses from rats subjected to zinc deprivation or to food restriction than in controls. The lower insulin content of fetal pancreata from zinc-deficient rats was related to a lower than normal proportion of insulin-containing beta cells. The lower insulin content of fetal pancreata from rats subjected to food restriction was related to a less than normal amount of insulin per beta cell. Glucagon concentration in the fetal pancreas was lower than normal in response to zinc deficiency but not to food restriction. Fetal hormone release in vitro was also influenced by the maternal diet. The rate of insulin secretion in vitro was normal in fetuses from zinc-deficient rats, but was accelerated in those from females subjected to calorie restriction. The rate of glucagon secretion in vitro was lower than normal in the pancreata of zinc-deficient fetuses. We conclude that insulin and glucagon levels in the fetus were affected by maternal zinc deficiency and, to a lesser extent, by calorie restriction.